int e l RESET OPTIONS (VERSION 1.1 ONLY) PROG6 Does the same thing as PROG5, but CALLS external program memory location 4039H during a RESET or power-up sequence. This option also requires the user to put the character 0A5H in external memory location 5FH to insure that external RAM will not be cleared during RESET or power-up. The user must put an assembly language RESET routine in external memory location 4039H or else this RESET mode will crash. When the user returns from the customized assembly language RESET routine, three options exist:
OPTION 1 FOR PROG6 If the CARRY BIT is CLEARED (CARRY = 0) upon return from the user RESET routine MCS BASIC- 52 will enter the auto-baud rate determining routine. The user must then type a space character (20H) on the terminal to complete the RESET routine and produce a RESET message on the terminal. OPTION 2 FOR PROG6 If the CARRY BIT is SET (CARRY = 1) and BIT 0 of the ACCUMULATOR is CLEARED (ACC. 0 = 0) MCS BASIC-52 will produce the standard sign-on message upon return from the user supplied RESET routine. The baud rate will be the one that was saved when the PROG6 option was used. OPTION 3 FOR PROG6 If the CARRY BIT is SET (CARRY = 1) and BIT 0 of the ACCUMULATOR is SET (ACC.
0 = 1), MCS BASIC-52 will execute the first program stored by the user in EPROM (starting address of the program is 8010H) upon return from the user supplied RESET routine. - 146 -